1. Field of the Invention
The present invention relates to a pixel electrode structure of a display device. More particularly, the present invention relates to a pixel electrode structure that is adaptive for improving a display quality of an image.
2. Description of the Related Art
In recent years, with the development of an information processing apparatus for processing massive data, a display device that displays the data processed at the information processing apparatus as an image has been actively developed. As the display device, a flat panel display device, representatively such as a liquid crystal display (LCD) device, a plasma display panel (PDP), or an organic light emitting device (OLED) is mainly used.
A twisted nematic (TN) mode, which is one kind of an LCD device, has advantages such as a rapid response speed and a low driving voltage. Whereas, the TN mode LCD device has a drawback that a viewing angle is not so good due to the refractive index anisotropy of liquid crystals, because the liquid crystal molecules are aligned along an electric field vertically applied thereto.
To address the drawbacks of the TN mode LCD device, an in-plane switching (IPS) mode LCD device has been developed recently.
In the IPS mode LCD device, since the electrical field is horizontally applied to the liquid crystals in parallel with the substrate, it is possible to obtain excellent viewing angle characteristic compared with the TN mode LCD device.
In order to form the horizontal electric field in parallel with the substrate, the IPS mode LCD device employs a comb-shaped pixel electrode. FIG. 1 is a plan view of a pixel electrode structure applied to an IPS mode LCD device according to a related art.
Referring to FIG. 1, a common electrode 3 is formed on a substrate 1. The common electrode 3 is a transparent conductive layer, and the substrate 1 is the lower substrate of the LCD device.
Although not shown, an insulating layer is disposed on the common electrode 3 such that it covers the common electrode 3, and a plurality of pixel electrodes 5 are disposed on the insulating layer. The plurality of pixel electrodes 5 are disposed on positions of the insulating layer corresponding to the common electrode 3 such that they are arranged in parallel. The pixel electrodes 5 disposed on the insulating layer, for example, may be formed of a transparent conductive material.
A pair of neighboring pixel electrodes 5 in the related art IPS mode LCD device have the same width W, respectively. The pair of neighboring pixel electrodes 5 with the same width W are arranged on the insulating layer such that they are separated by the same space L.
The pixel electrodes 5 having the same width W and the same space L may be commonly applied to the IPS mode LCD device and a fringe field switching (FFS) mode LCD device. Generally, in the IPS mode LCD device and the FFS mode LCD device, a display quality of an image is determined by the space L and the width W of the pixel electrode 5.
As denoted by the solid lines in FIG. 1, if the neighboring pixel electrodes 5 are equally separated by the space L and have the same width W in the IPS mode LCD device and the FFS mode LCD device, the display quality of the image can be improved. However, in reality, the space L between the neighboring pixel electrodes 5 and the width W of the pixel electrodes 5 may not be uniform (i.e., they vary randomly, without any preset pattern) as shown by the dotted lines in FIG. 1. As a result, the display quality of the image displayed by the related art IPS mode LCD device and the related art FFS mode LCD device can be seriously degraded.